The present invention relates to a textile sheetlike structure in the form of a composite material, in particular for protection against biological and chemical noxiants and poisons, such as biological and chemical warfare agents, as defined in the preamble of Claim 1. Furthermore, the present invention relates to a process for producing such material. The present invention further relates to the use of this textile sheetlike structure for producing protective materials of any kind, such as for example protective suits, protective gloves, protective footwear (protective boots for example) and other protective clothing items, and also protective covers (e.g. to transport casualties for example), sleeping bags and the like, not only for the military sector but also for the civilian sector, in particular for NBC utilization. Finally, the present invention relates also to the aforementioned protective materials themselves.
Activated carbon has fairly unspecific adsorptive properties and for this reason is the most widely used adsorbent. Legislative regulations as well as the rising sense of responsibility for the environment lead to a rising demand for activated carbon. Furthermore, activated carbon is also employed in protective materials against chemical and biological noxiants and poisons.
Activated carbon is generally obtained by carbonization (also referred to by the synonyms of smoldering and pyrolysis) and subsequent activation of carbonaceous starting materials, preferably compounds or materials which lead to economically reasonable yields. The weight loss through the split-off or cleavage of volatile constituents in the course of carbonizing and through the burn-off in the course of activating are immense. Whereas carbonization is the conversion of a carbonaceous starting material into carbon, the subsequent activation involves a controlled burn-off of the activated carbon to increase the porosity and thus the internal surface area (pore volume) and consequently the performance capability of the activated carbon. The properties and compositions of the activated carbon produced, whether finely or coarsely porous, firm or brittle, is also dependent on the starting material. Examples of customary starting materials are coconut shells, wood wastes, turf, bituminous coal, pitches, polymers, but also plastics which play a part, inter alia, in the production of activated carbon wovens. For further details concerning the production of activated carbon, see for example H. v. Kienle and E. Bäder, “Aktivkohle und ihre industrielle Anwendung” [Activated Carbon and Its Industrial Application], Enke Verlag Stuttgart, 1980.
Activated carbon is used in various forms: pulverized carbon, splint coal carbon, granular activated carbon, molded carbon and spherical activated carbon as well as in the form of activated carbon fibres, in particular in the form of sheetlike structures composed of activated carbon fibres. Such activated carbon fibre sheetlike structures are employed, for example, in the production of protective materials of any kind as mentioned above.
The production of activated carbon fibre sheetlike structures is described, for example, in WO-A-98/041678 and its equivalents EP 0 966 558 B1 and DE 698 09 718 T2 or in WO-A-01/70372 and in DE 196 47 366 A1. The general procedure involved is to lead a textile sheetlike structure composed of a suitable carbonizable starting material (examples being cellulose, viscose, cotton, polyacrylonitrile, etc.) through a carbonizing and activating kiln or furnace, wherein the maximum web width of the starting material (i.e. the maximum breadth of the starting textile material to pass the kiln or furnace) which can be used is limited by the kiln or furnace dimensions. The carbonization with subsequent activation, moreover, causes an appreciable shrinkage of the material, so that the end-product, i.e. the ready-produced carbonized and activated carbon fibre sheetlike structure, has a distinctly smaller web width if compared with the starting material, with shrinkage values of up to 30% or more for the end-product compared with the starting material occurring in the course of production, depending on the production process.
Customary carbonizing and activating kilns or furnaces for these purposes generally cannot be used to fabricate activated carbon fibre sheetlike structure webs more than 120 cm wide. This leads to the decisive disadvantage of a poor making-up utilization of in some instances below 60% of this material when it is processed or to be more precise cut for the production of the aforementioned protective materials (for example NBC protective suits and the like). The term “making-up utilization”—sometimes also synonymously called “making-up yield factor”, “utilization degree”, “utilization factor”, “utilization rate”, “exploitation degree of the material” etc.—characterizes the percentage of the starting material which may be utilized to manufacture the end-product, i.e. the ready-made protective garment; when the making-up yield factor is e.g. only 60% and below, this means that 40% and more of the starting textile material is lost (i.e. it cannot used) due to the cutting and subsequent processing of the starting textile material to the desired final products (e.g. protective garments etc.).
The object of the present invention consequently is to provide a process and a material at least substantially avoiding or at least minimizing the above-described disadvantages of the prior art.
A further object of the present invention is to provide a process for producing activated carbon fibre sheetlike structures having greater web width to thereby permit an improved making-up utilization in the course of the production of the aforementioned protective materials (for example protective suits and the like).
To solve the problem described above, the present invention proposes a textile sheetlike structure in the form of a composite material as described herein. Various advantageous embodiments of textile sheetlike structure of the present invention are also disclosed herein.
The present invention further provides protective materials, in particular protective suits, protective gloves, protective footwear (protective boots, for example) and other protective clothing items and also protective covers (e.g. to transport casualties for example), protective sleeping bags and the like which are produced using the textile sheetlike structure of the present invention or which comprise the textile sheetlike structure of the present invention. The present invention thus also relates to the use of the textile sheetlike structure of the present invention for producing the aforementioned protective materials.
The present invention finally relates to a process for producing the textile sheetlike structure of the present invention.